Piston.



.F. D. WARD.

PISTGN.

` APPLICATION FILED Nov. 9, Ien.

1 $282,594. Patented Oct. 22, 1918.-

I @IV FRANK D. WARD, OF NEW YORK, N. Y.

PISTON.

Specification of Letters Patent.

Patented Oct. 22, 1918.

Application led November 9, 1917. Serial No. 201,056.

To all whom t may concern:

Be it known that I, FRANK D. WARD, a citizen of the United States of America, and residing inthe city, county, and State of New York, have invented certain new and useful Improvements in Pistons, of which the following is a specification.

My invention relates to pistons and particularly to pistons provided with cup leather packings, the object of my invention being to provide the piston head with a member coperating with the usual follower to hold the packing tight and insure its proper function.

In the accompanying drawings,

Figure 1 is a broken side elevation of a cylinder, showing, in section, a piston head in which my invention is embodied in one form;

Figs. 2 and 3 are sections on the lines 2-2 and 3 3, Fig. 1, respectively.

Considerable difficulty is experienced in keeping tight the cup leather packing of piston heads. In spite of the common use of a cup-shaped metal follower, between the flange of which and the wall of the piston cylinder the cup leather flange is confined, a certain amount of longitudinal play of the packing flange occurs during the Operation of the piston, which fleXes the leather at the angle between the flange andthe central disk portion of the packing. In the course of time, the leather seems to become weakened at this point, and leakages occur which decrease the efficiency of the engine. I have now provided a device associated with the piston head, which bears against the end of the cup leather flange and not only holds the latter against flexion, but also tends to compress the flange, thus insuring the maintenance of a tight fit of the piston within the engine cylinder.

In the embodiment of my invention here illustrated, I have shown only a portion of the engine cylinder 10, within which works the piston, carried by the rod 11 and having the usual head plate 12, resting against the shoulder formed by the reduced threaded stem 13 of the piston rod. Against the plate 12 rests the central disk portion of the cup leather 14, the annular flange 15 of which lits snugly within the cylinder. 'The cup-shaped metal follower 16, screwed upon the stem 13, holds the packing 14 in position, and it tends to maintain the cup leather flange firmly against the wall of the cylinder. In these features, the construction is of common type; but, as above stated, in spite of the use of a cup-shaped follower 16, there is, in practice, constant flexion of the cup leather at the angle 18, which causes the packing to detericrate and lessens the elliciency of the engine through leakage at this point.

The present invention provides for a piston of this general type, a cap member 19 of cup-shape. Its annular flange 20 is of less diameter than the cylinder l0, so that it does not bear against the inner wall thereof, but is nevertheless of sufficient diameter to sleeve outside the flange 17 of the follower 16 and bear against the flange 15 of the packing. This cap is carried by three screws 21, taking into tapped holes in the follower 16. The heads 22 of these screws work in guide thimbles 23 on the cap, and form abutments for springs 24 interposed between said heads and the bottoms of the thimbles. The springs 24: tend constantly to force the cap 19 toward the abutment plate l2 of the piston head, and thus compress the packing flange 15. The outer ends of the thimbles 23 areclosed by screw plugs 25, so'that the cap 19 presents an imperforate face to the pressure medium entering the cylinder from' the direction of the arrow X. Consequently, A

when power is on the cylinder, the cap 19 is forced against the packing flange l5 not only by the action of the springs 241, but also by the motive power. Thus, the pressure of the cap upon the cup leather flange is strongest at the time when it is most needed, viz., when power is on the cylinder. In order to increase the effect of the cap flange 20, the edge of the latter which engages the flange of the cup leather, may be beveled, as at 26, to spread the flange 15 outward against the wall of the cylinder. This is not at all essential, hmvever, to the effectiveness of the cap 19. End pressure alone on the flange 15 of the cup leather is sufficient to hold the packing tight, without a spreading action. It is found that using a cap, such as 19, the flange 15 does not deteriorate at the angle 18, even after long use, and the packing is constantly maintained tight.

Various modifications in detail of construction will readily occur to those skilled in the art which do not depart from what I claim as my invention.

I claim:

1. In a piston, a cup leather packing a cup-shaped follower therefor, in combination with a member carried by said follower and longitudinally displaceable with relation to the piston head and bearing against the free edge of the cup leather flange to hold the latter rigid. y

2. In a piston, a cup leather packing a cup-shaped follower therefor, in combination with a member carried by said follower and longitudinally displaceable with relation to the piston head and bearing against the free edge of the cup leather flange, to-

gether with means for pressing said member against said flange.

3. In a piston, a cup leather packing al cup-shaped follower therefor, in combination with a member carried by said follower and longitudinally displaceable with relation to the piston head and bearing against the free edge of the cup leather flange, together with spring means for pressing said member against said flange.

1l. In a piston, a cup leather packing aV cup-shaped follower therefor, in combination with a member carried by said follower' and longitudinally displaceable with relation to the piston head and bearing against the free edge of the cup leather flange, said member being subject tothe action of the pressure medium in the cylinder.

5. In a piston, a cup leather packing a cup-shaped follower therefor, in combination with a member carried by said follower and longitudinally displaceable with relation to the piston head and bearing against the free edge of the cup leather flange, said member being of cup-shape and its flange 'being opposed to the flange of the packing and bearing against the same.

6. In a piston, a` cup leather packing a cup-shaped follower therefor, in combination with a member carried by said follower and longitudinally displaceable with relation. to the piston head and bearing against the free edge of the cup leather flange, said member being of cup-shape and its flange being opposed to the flange of the packing and bearing against the same, and presenting an imperforate surface to the pressure medium in the cylinder.

7. rI`he combination with a. piston head having a cup leather and cup follower within the same, of a cup-shaped cap the flange of which sleeves between the cylinder wall and bears upon the edge of the cup Vleather flange. Y

8. rlhe combination with a piston head having a cup leather and cup follower within the same, of a cup-shaped cap the flange of which sleeves between the cylinder wall and the flange of the cup-shaped follower and bears upon the edge of the cup leather flange, said cap having freedom of longitudinal displacement with relation to the piston head.

9. The combination with a piston head having a cup leather and cup follower within the same, of a cup-shaped cap the flange of which sleeves between the cylinder wall and the flange of the cup-shaped follower and bears upon the edge of the cup leather flange, said cap having freedom of longitudinal displacement with relation to the piston head, together with spring means for pressing said cap toward the cylinder head.

10. The combination with a piston head having a cup leather and cup follower within the same, of a cup-shaped cap, the flange of which sleeves between the cylinder wall and the flange of the cup-shaped follower and bears upon the edge of the cup leather flange, said cap having freedom of longitudinal displacement with relation to the piston head, and presenting an imperforate face to the pressure medium introduced into the cylinder.

11. A piston having a cup-shaped packing, a member spaced from the piston cylinder wall to form therewith a cylindrical chamber within which the flange of the cup packing is closely confined, `in combination with a cap constantly bearing against the free margin of the cup packingA flange to prevent flexion at the joint between said flange and the body of the packing.

12. A pistonvhaving a cup-shaped packing, a member spaced from the cylinder wall Vto form therewith a cylindrical chamber within which the flange of the cup packing is closely confined, in combination with a spring-pressed member constantly bearing against the free margin Vof the cup packing flange to prevent flexion at the joint between said flange and the body of the packing.

13. For use with a piston having a cupshaped packing, a follower element comprising a cup-shaped follower adapted to bear against the body of the packing and confine the flange thereof between the'flange of said follower and the wall of the piston cylinder, and an oppositely faced cup-shaped cap carried by said follower and sleeving thereon to permit the flange of said cap to bear against the margin of the cupshaped packing.

14. For use with a piston having a cupshaped packing, a follower element comprispermit the flange of said cap to bear against ing a cup-shaped follower adapted to bear the margin of the cup-shaped packing, toagainst the body of the packing and confine gether with spring means tending. constantly 10 the flange thereof between the flange of said to press said cap toward the follower.

follower and the wall of the piston cylinder, In testimony whereof I have signed my and an oppositely faced cup-shaped cap carname to this specification. ried by said follower and sleeving thereon to FRANK D. WARD.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents. Washington, D. C. 

